The Chimp frame has a nice 4mm thick CF baseplate/arms, good motor protection, and adjustable GoPro mount that is good for carrying small payloads. The Flip 32 Omnibus came highly recommended.
If you decide to build this, use Tiger F80 motors if you can afford them. Either the 1900 or 2200KV and run 4 or 5S high ampacity battery cells.
How's the build coming together? My Chimp should be arriving in the next couple days.
Did you remove the casing from the receiver? I'm sure if you removed the pins from your FC, got a smaller receiver and trimmed a lot of the excess wire you could fit it all. Have a look at mine. I managed to fit it all in there with a nice pocket of space above the FC. I love the design of this frame and I'm looking forward to many flights.
No real need to switch to F4 at this point. I'd probably just de-pin the one you've got. You could even cut the pins and solder to the tips. But if it's too much trouble you could get the original Omnibus F3 for about $23. It mainly lacks the current sensor over the pro, so you wouldn't be missing too much.
Did you add those pins to the FC? Why not solder the wires directly to the board? My GEP-TX5 is well under way. I should be finished this week. Can't wait to see how it flies.
What sort of range do you get with the SP831/833 vtx?
It's about the same as some of my other 200mW VTX when set to 600mW. I'm not sure why. It can get a bit noisy behind a tree at 100m.